连作障碍消减措施对棉花产量形成和化感自毒作用的影响

目的 研究新疆塔里木盆地 棉花在不同连作障碍消减措施下的化感自毒效应和评价方式。方法 采用田间小区试验,研究不同消减措施对塔里木盆地棉花土壤养分净变化、植株生长、产量、种子发芽的化感自毒效应。结果 不同的消减措施对棉花各项指标和化感综合指数有显著差异;CRI处理后土壤中碱解氮净变值最小,CRR处理后土壤速效磷减少量最大,而速效钾则是RIM处理下减少量最大,不论是0~20 cm土层还是20~40 cm土层均是如此; RIM和CM对棉花株高、果枝台数、籽棉产量都具有显著的促进作用,RIM对棉花单铃重具有显著的促进作用,微生物肥料在其中起到了重要的作用;碱解氮的净变值与棉花籽棉产量之间呈负相关关系,而速效磷和速效钾的净变值则与棉花籽棉产量呈负相关关系,其中二次多项式达到显著或极显著水平;将选择的各指标按公式进行RIs计算和比较,发现各消减措施都能表现出一定的化感促进作用,其中以RIM处理(棉花-油菜间作+微生物肥料)下的RIs最大,化感促进作用最强,而不同浸提浓度下则以1:10表现的最佳,RIs均为正值且化感综合指数最大。结论 生产中采用棉花-油菜间作+微生物肥料是减轻棉花连作障碍有效和可行的方法。

Effects of Different Abatement Measures of Continuous Cropping Obstacle on Yield Formation and Allelopathic Autotoxicity of Cotton (Gossypium hirsutum L.)

Objective To explore the cotton allelopathic autotoxicity effects and evaluation methods under different continuous cropping obstacle abatement measures in Tarim Basin, China.Method The field plot tests were adopted and four measures, continuous cropping with microbial fertilizer (CM), cotton - rape rotation (CRR), cotton-rape intercropping (CRI) and cotton - rape intercropping with microbial fertilizer((RIM), were used in this experiment. Then, some effects of the abatement measures were concluded, and RIs index and evaluation results raised. Result The results showed there were significant differences between different indexes and allelopathic synthetical index under different abatement measures. Both in the 0-20 cm soil layer and the 20-40 cm soil layer, the net change value of alkali-hydrolyzed nitrogen in the soil after CRI treatment was the minimum, and the decrease amount of readily available phosphorus in the soil after CRR treatment was the maximum, while the decrease amount of readily available potassium was the maximum under RIM treatment. RIM and CM had significant promoting effects on cotton plant height, number of fruit branches and cotton yield, meanwhile, RIM had significant promoting effects on single boll weight of cotton, among which microbial fertilizer played an important role. The net change of alkali-hydrolyzed nitrogen was negatively correlated with seed cotton yield, while the net change of readily available phosphorus and readily available potassium were negatively correlated with seed cotton yield, where the quadratic polynomial reached the significant or extremely significant level. After choosing the indexes according to the formula, RIs was calculated and compared, then it was found that there was a certain degree of allelopathy promoting effect under all the control measures, in which under RIM treatment (cotton-rape intercropping with microbial fertilizer), RIs was the largest and allelopathy promotion was the strongest, while it had the best effect and the largest RIs under the extracting concentration of 1∶10.Conclusion The way of cotton-rape intercropping with microbial fertilizer is an effective and feasible method to reduce the continuous cropping obstacles of cotton.